About this trial
This study investigates the impact of ∆9-tetrahydrocannabinol (THC) and cannabidiol (CBD) on recognition memory in healthy, regular cannabis users. Participants complete the same recognition memory task after self-administering one of two different strains of cannabis flower one day and while not intoxicated another day. Event-related potentials (ERPs) are measured via electroencephalogram (EEG) during the recognition memory task. Blood is collected to quantify THC and CBD exposure. Participants also complete self-report measures of medical history, sleep quality, subjective cognitive function, physical activity, psychological functioning, substance use, and acute drug effects.
Eligibility criteria
This trial accepts healthy volunteersQualifiers
Must be between the ages of 21 and 40 and provide informed consent;
Must be right-handed (Laterality Quotient > 60 on Edinburgh Handedness Inventory - Short Form136);
Must use cannabis at least 4 days during the month;
Must be a cannabis user for at least a year;
Disqualifiers
None
Trial population
Community sample of healthy, regular cannabis users in the Boulder/Denver areas.
Trial design
Cohort
Prospective
Treatments tested in this trial
Cannabis (smoked flower)
DrugSelf directed use (ad libitum)
Treatment groups
Trial outcomes
Primary outcomes
Difference in ERP amplitude (FN400)
The FN400 event-related potential (ERP) old/new effect will be measured using electroencephalography (EEG) during a recognition memory test. The FN400 reflects familiarity-based memory retrieval and is defined as the mean ERP amplitude difference between correctly recognized previously presented items ("hits") and correctly rejected novel items ("correct rejections") at mid-frontal electrode sites during the 300-500ms post-stimulus interval.
Difference in ERP amplitude (parietal)
The parietal ERP old/new effect will be measured using EEG during a recognition memory test. The parietal old/new effect reflects recollection-based memory retrieval and is defined as the mean ERP amplitude difference between hits and correct rejections at parietal electrode sites during the 500-800ms post-stimulus interval.
Difference in retrieval memory accuracy
Behavioral accuracy during recognition memory test will be assessed by the number of hits and correct rejections made during memory recall. Retrieval memory accuracy will be compared between intoxicated and not-intoxicated sessions.
Difference in retrieval memory performance
Memory performance will be assessed via reaction time, measured by a photocell during recognition memory testing and concurrent EEG. During the recall phase, a light indicator will appear in the bottom-right corner of the stimulus screen when a prompted image is presented, activating the photocell. This indicator disappears once the participant responds. The interval between stimulus onset and the participant's "new" or "old" response is used as the reaction time measure for both intoxicated and non-intoxicated sessions. Retrieval memory performance will be compared between intoxicated and not-intoxicated sessions.
Secondary outcomes
Change in Positive and Negative Affect Schedule (PANAS)
The PANAS is a Self-report measurement of positive and negative affect that will be administered at all times of the Mobile sessions: the pre-use and post-use timepoints of the intoxicated session, well as the not-intoxicated session. The PANAS will be used twice at the intoxicated session to measure changes in mood before and after cannabis use. The survey presents a 20-item scale from 1 (very slightly or not at all) to 5 (extremely), with a higher score on the positive affect scale indicating higher positive affect and a higher score on the negative affect scale indicating higher negative affect.
Change in Drug Effects Questionnaire (DEQ)
The DEQ is a 5-item visual analogue scale that measures acute drug effects, with prevalent use across numerous drug studies. Specifically, the questionnaire measures strength of the effects of cannabis as well as the desirability of the effects. Participants answer questions on a range from 0 - 100, with higher values for each item indicating greater drug effect or desire. The specific items related to drug "liking" and "wanting more" have been associated with harmful drug use. Participants will be administered the DEQ at all time points of the Mobile sessions to assess differences following intoxication.
Change in Addiction Research Center Inventory (ARCI-M)
The ARCI-M is a self-report measure of subjective effects of marijuana in addition to drug-induced euphoria, stimulant-like effects, intellectual efficiency and energy, sedation, dysphoria, and other somatic effects. This is a 12 item true-false task, in which higher (true) scores indicate greater intoxication. Participants will be administered the ARCI-M at all time points of the Mobile sessions to assess differences following intoxication.
Change in Marijuana Craving Questionnaire (MCQ)
The Marijuana Craving Questionnaire is a self-report measure of marijuana craving that will be administered at all time points during the Mobile sessions. Participants complete 8 questions ranging from 0 - 10, with a higher score indicating greater cannabis craving and somatic symptoms. The primary focus of this questionnaire will be the effect of intoxication on reporting.
Other outcomes
Exploratory: Correlations between genes related to cannabinoid metabolism, cannabis-related behavior, and neurocognitive function with ERPs and recognition memory performance
DNA will be extracted from 3.0 ml of blood from the baseline session. After extraction, DNA will be quantified and stored at -80° for analysis. DNA will be collected to look at differences in epigenetic and single nucleotide polymorphisms (SNPs) in participants. Due to the rapidly changing landscape of genetic science, the DNA samples collected in this study are primarily for bio-banking purposes. The analysis of these genetic samples is expected to be performed at a future date to contribute to the current study and/or future studies. Participants will be allowed to opt out of storage of genetic samples for future research.
Exploratory: Moderation of primary effects by baseline sleep quality using the Patient-Reported Outcomes Measurement Information Systems (PROMIS)
Baseline measurement of sleep disturbance, assessing participant's quality and patterns of sleep over the last seven days. Participants complete 4 items, for a total scale score from 4 - 20, with higher scores indicating more sleep disturbance.
Exploratory: Moderation of primary effects by baseline affective symptoms using the Depression Anxiety Stress Scale (DASS)
Baseline assessment of affective symptoms. Participants complete the Depression, Anxiety, and Stress Scale-21 (DASS-21), a 21-item measure consisting of three 7-item subscales assessing depression, anxiety, and stress/tension. Higher scores indicate greater symptom severity within each domain. Acute drug-effect measures will be collected at each study session, including before and after participants self-administer their assigned cannabis strain during mobile laboratory sessions.
Exploratory: Moderation of primary effects by baseline substance use history using the Timeline Followback (TLFB)
The TLFB is used to assess daily substance use for 30 days prior to the Baseline Appointment and 3-7 days prior to the later sessions. Our modified TLFB procedure will estimate both frequency of marijuana use and amount used per day, using visual stimuli as well as the method of administration.
Sponsors and contacts
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L. Cinnamon Bidwell
Lead sponsor
University of Colorado, Boulder
Sponsor institution
National Institute on Drug Abuse (NIDA)
Collaborator